Patent GB-451549-A (GB)
Title: Improvements in or relating to the enclosure of natural history specimens and other solid objects in urea and like resins
IPC: G09B23/36
Filed: 1935-10-04
Abstract: Solid articles, e.g. rock or stone specimens, insects, or other natural history specimens, are enclosed in solid transparent masses for preservation, display, &c. by forming a layer of a condensation product of urea or a derivative thereof and formaldehyde in its viscous presolidification stage, applying to the surface of this layer the object previously coated or impregnated with the condensation product to eliminate air bubbles, and forming the upper portion of the mass by pouring in more of the condensation product after the surface of the first layer has been partially solidified. Where the object is of greater specific gravity than the condensation product it is placed in position after partial solidification of the surface of the lower layer, and when it is of smaller specific gravity it is placed in position and the partial solidification is subsequently effected or it may be placed in position when partial solidification has been affected but the surface is still in a sticky condition.  The condensation product may be obtained by adding 2 kgs. of a 50 per cent. aqueous solution of urea to 10 kgs. of formaline, further additions of the solution 1 kg. at a time being made until 5 kg. has been added in all.  A catalyst such as ammonia or formic acid may be employed.  In an example, an insect is killed in formaline solution, coated with the condensation product rubbed in with a brush, and laid on the upper surface, which has been dried at about 85 DEG  C., of a layer of the product which half fills a mould.  A small quantity of the product is then poured on the insect and after further solidification the rest of the product is added and solidified in the mould by drying at about 45 DEG  C.ALSO:Solid articles, e.g. rock or stone specimens, insects, or other natural history specimens, are enclosed in solid transparent masses for preservation, display, &c., by forming a layer of a condensation product of urea or a derivative thereof and formaldehyde in its viscous presolidification stage, applying to the surface of this layer the object previously coated or impregnated with the condensation product to eliminate air bubbles, and forming the upper portion of the mass by pouring in more of the condensation product after the surface of the first layer has been partially solidified. Where the object is of greater specific gravity than the condensation product it is placed in position after partial solidification of the surface of the lower layer, and when it is of smaller specific gravity it is placed in position and this partial solidification is subsequently effected or it may be placed in position when partial solidification has been affected but the surface is still in a sticky condition.  The condensation product may be obtained by adding 2 kgs of a 50 per cent. aqueous solution of urea to 10 kgs. of formaline, further additions of the solution 1 kg. at a time being made until 5 kg. has been added in all.  A catalyst such as ammonia or formic acid may be employed.  In an example, an insect is killed in formaline solution, coated with the condensation produce rubbed in with a brush, and laid on the upper surface, which has been dried at about 85 DEG  C., of a layer of the product which half fills a mould.  A small quantity of the product is then poured on the insect and after further solidification the rest of the product is added and solidified in the mould by drying at about 45 DEG  C.